SOUND AS A DIRECTING INFLUENCE IN THE MOVEMENTS 



OF FISHES. 



By G. H. PARKER, S. D., 

 Professor of Zoology, Harvard University. 



The detection of the direction of a sound by the human ear is not generally accom- 

 plished with great accuracy, especially when the source of the sound is placed sym- 

 metrically in reference to the two ears. In man the one sense organ concerned in these 

 operations is the ear. In fishes there are at least three sets of organs that may be 

 involved in like operations, the skin, the lateral-line organs, and the ear, for though 

 the function of hearing has been denied to fishes by some recent workers, there seems 

 to be sufficient evidence to warrant the conclusion that at least certain fishes hear. 

 Whether, however, fishes respond to sounds in a directive way or not is a matter that, 

 so far as I am aware, has never been subjected to experimental test. It is the puqjose 

 of this paper to discuss the directive influence of sounds on the movements of fishes, 

 and it is believed that work such as this will throw light on the question of the temporary 

 distribution of fishes in reference to such centers of sound production as are afforded 

 by naval gun practice, etc. 



In attempting to test the question of the directive influence of sounds upon the 

 movements of fishes, experiments were first tried in a large floating cage anchored in 

 open sea water, but it was soon found that the disturbances produced by the wind 

 and the sunlight were too great to admit of conclusive work, and recourse was finally 

 had to experiments conducted in nmning sea water indoors. These experiments were 

 carried out in the Biological Laboratory at the Woods Hole Station of the United States 

 Bureau of Fisheries. 



The fishes were tested in a tank about 50 cm. wide, 60 cm. deep, and 100 cm. long. 

 The tank was made of wood 3.5 cm. thick; on the inside its walls were painted black, 

 its bottom white. At one end of the tank there was a controllable inlet of sea water 

 and at the other end an outlet. When the water in the tank was high enough to flow 

 out at the outlet it was within a few centimeters of the top. The tank stood on a strong 

 table and its upper edge was provided with a low black curtain so that persons moving 

 about the laboratory could not be seen by the fishes. The tank was illuminated by 

 an incandescent electric light hung directly over its center and some feet above the 

 level of the water, or by diffusely reflected daylight from a white ceiling above. At 

 each end of the tank a cord was attached to the ceiHng and from a hook on the end 

 of the cord an iron ball was suspended, the whole device being so adjusted that when 

 at rest the ball just touched the middle of the end of the tank. The ball, like the bob 

 of a long pendulum, could be withdrawn from the end of the tank, and when released 



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